Clinical heterogeneity is one of the basic facts of Alzheimer's disease. With this renewal application the DC Davis ADC further defines its long-standing interest in that heterogeneity to focus on two interconnected sets of factors, which may modify the clinical expression of this disorder, namely cerebrovascular disease and ethnicity. The goal of the Clinical Core is to assemble the subjects and clinical data needed to support and expand the research programs of ADC investigators, to facilitate the work of other investigators at Davis, and to contribute to the larger research community. The aims of the Core are: 1) To create cohorts of subjects who may participate in dementia related studies, and to follow selected subjects to create a longitudinal cohort and to maximize autopsy rates. 2) Diversify our subject population by recruiting large numbers of African American and Hispanic subjects, increasing the number of subjects with vascular risk factors and cerebrovascular disease, and by substantially increasing the number of subjects with MCI and or normal cognitive function. 3) Acquire high quality clinical data, including diagnosis, the UDS, and measures well suited for longitudinal measure and to maintain quality control of the data. 4) Facilitate and promote dementia research at Davis by helping investigators recruit subjects and train clinical investigators. Three of the most basic functions of the Core are subject recruitment, diagnosis, and assignment of subjects to research protocols. Subjects are recruited to the ADC through two dementia clinics, one in Sacramento, one in Martinez, and through a sizeable community outreach effort. In the community outreach program ADC recruiters directly approach senior citizens in the community to ask their participation. This approach, new in the concluding grant cycle, resulted in much larger numbers of minority participants, and more persons with cerebrovascular risk factors. The number of subjects with MCI also greatly increased. Regardless of where they are recruited, all subjects receive the same diagnostic evaluation, which includes the UDS measures, and are diagnosed according to the same procedures. After diagnosis, subjects are assigned to either the cross sectional cohort, or the longitudinal cohort. Subjects entering the longitudinal cohort receive additional studies including MRI, DNA/serum banking, and special neuropsychological studies, and are followed to autopsy if possible. These two cohorts play complementary roles in the Center, the CSC providing subjects to studies that require only diagnosis and/or baseline characteristics, while the LC provides a powerful core of baseline brain imaging and longitudinal neuropsychological, functional, and other clinical indices for studies of change or conversion.